Rotary cylinder internal combustion engine

ABSTRACT

The four-stroke internal combustion engine comprises a stator having induction and exhaust ports, a rotor rotatable in the stator and defining cylinders with the stator in which pistons connected to a crankshaft are slidable. A transmission device interposed between the crankshaft and rotor produces a given relative speed of rotation therebetween. The feature of the engine is that additional ports, comprising an inlet port and outlet port, are provided in the stator and each piston and corresponding cylinder cooperate with these additional ports in the course of a part of each revolution of the rotor to perform a pumping function.

United States Patent Froumajou Nov. 25, 1975 ROTARY CYLINDER INTERNAL1,331,749 2/1920 Freer 123/44 D COMBUSTION ENGINE 1,705,130 3/1929McKlusky l23/44 D 2,707,461 5/1955 Smith 123/44 E Inventor: ArmandFroumajou, Pontoise, 3,205,877 9/1965 Rychlik 123/44 D France [73]Assignees: Automobiles Peugeot, Paris; Regie Primary Examiner-clarenceGordon N i l des U i R l Attorney, Agent, or Firm-Burns, Doane, Swecker& Boulogne-Billancourt, both of Mathis France 22 Filed: Jan. 15, 1975ABSTRACT [211 Appl 541,326 The four-stroke internal combustion enginecomprises a stator having induction and exhaust ports, a rotor rotatablein the stator and defining cylinders with the [30] Foreign ApplicationPriority Data stator in whichrpistons connected to a crankshaft are Jan.24, 1974 France 74.02390 slidable. A transmission device interposedbetween the crankshaft and rotor produces a given relative speed [52]US. Cl 123/44 D of rotation therebetween, the feature of the engine is[51] Int. Cl. F02B 57/04 that additional ports, comprising an inlet portand out- Field Of Searchm 12 4 R, 44 A, 44 B, let port, are provided inthe stator and each piston and 3/44 C, 44 E corresponding cylindercooperate with these additional ports in the course of a part of eachrevolution [56] References Cited of the rotor to perform a pumpingfunction.

UNITED STATES PATENTS 8 Claims, 3 Drawing Figures 1,138,388 5/l9l5Levering 123/44 D I 4 -lll 4 nllnqlll U.S. Patent Nov. 25, 1975SheetlofZ 3,921,602

U.S. Patent Nov. 25, 1975 Sheet 2 of2 3,921,602

ROTARY CYLINDER INTERNAL COMBUSTION ENGINE The present invention relatesto a four-stroke internal combustion engine whose cylinders are arrangedradially in a rotor. I

A first known arrangement employed in such engines consists inmaintaining the pistons constantly applied against a fixed centre camwhose profile is such that each piston undergoes two to-and-fromovements per revolution of the rotor. These arrangements have twoserious drawbacks: on one hand, the speed of rotation of the rotor ishigh and gives rise to piston ring problems very difficult to solve and,on the other, the linear contact on the cam results in excessive Hertzpressures.

In another arrangement the pistons of each cylinder are connected by aconnecting rod to the crankpin of a crankshaft, the ratio between thespeeds of rotation of the rotor containing the cylinders and thecrankshaft being such that each piston undergoes an even number ofto-and-fro movements per revolution of the rotor. In these engines, thedesire for maximum compactness is at the cost of balance. Indeed, thereis incompatibility between great compactness, which can only be achievedwith rather large inclinations of the connecting rods, and good balancewhich requires small inclinations.

Moreover, there is disclosed, in particular in the Certificate ofAddition No. 95,879 attached to French Pat. No. 1,453,504, an internalcombustion engine comprising a crankshaft provided with an eccentriccrankpin, four fixed cylinders arranged in the form of a cross andhaving axes perpendicular to the axis'of the crankshaft, two pairs ofpistons each of which pair of pistons is mounted to rotate on a journalof a common balancing element whichis mounted to rotate on the crankpin,the axes of the journals and crankpin being parallel and contained inthe same plane, and the offset of the crankpin from the axis of thecrankshaft being equal to one half of the distance between saidjournals. Such an engine has a practically perfect balance.Unfortunately, as it is necessary to place at the head of each cylindera cylinder head having induction and exhaust valves and to provide meansfor controlling these valves, there results an assembly which isverylarge-and mechanically complex.

Now it is known that in an engine having four cylinders arranged in theform ofa cross in which the pistons located on the same axis are rigidlyinterconnected, if the cylinders are rotated about an axis perpendicularto the plane of the cylinders, the number of to-and-fro movementseffected by each piston per revolution of the cylinder blockisznecessarily odd. This is why this design of an engine having rotatingcylinder blocks has been proposed heretofore only for two-stroke enginesbut nevervfor four-stroke engines.

An object of the invention is to provide an internal combustion enginehaving rotary cylinders operating on the four-stroke cycle which isparticularly compact and as perfectly balanced as possible owing inparticular to the elimination of the connecting rod-crank systems. 1

According to theinvention, there is provided a fourstroke internalcombustion engine comprising a stator having induction and exhaustports, a rotor rotatably mounted in the statorand defining cylinders inwhich are received pistons connected to a crankshaft, and a transmissiondevice between the crankshaft and the rotor for establishingtherebetween a given relative speed. .wherein the stator has twoadditional ports. namely an inlet port and a delivery port, with whichadditional ports each cylinder and piston assembly cooperates in thecourse of a part of each revolution of the rotor for performing apumping function.

The invention is more particularly applicable to an engine having acrankshaft providedwith an eccentric crankpin, four cylinders arrangedin the form of a cross and having axes perpendicular to the axis of thecrankshaft, two pairs of pistons, each pair being mounted to rotate on ajournal ofa common balancing element which is rotatably mounted on thecrankpin, the axes of the journals and of the crankpin being paralleland contained in the same plane and the offset of the crankpin from theaxis of the crankshaft beingequal to one half of the distance betweensaid journals.

Another feature of this engine is that the rotor rotates in the statorabout an axis perpendicular to the axes of the cylinders, thetransmission device between the rotor and the crankshaft being such thatthe ratio between the speeds of rotation of the crankshaft and rotor isa positive or negative even whole number different from +2.

In a preferred embodiment, the direction of rotation of the crankshaftis opposite to that of the rotor and its speed of rotation is four-timeshigher so that it is possible to employ, per revolution of the rotor,fourto-andfro movements of each piston to achieve two completefour-stroke drive cycles and one to-and-fro movement of the piston toensure the pumping through said additional ports.

The invention will be described in more detail hereinafter with respectto a preferred embodiment with reference to the accompanying drawings inwhich:

FIG. 1 is a cross-sectional view of an engine according to theinvention; I

FIG. 2 is a sectionalview taken on line 2 2 of FIG.

1, and

FIG. 3 is a diagram showing the different phases of the cycle ofoperation of a cylinder and piston assembly for one revolution of therotor.

The engine according to the invention comprises a stator 1 having aroughly cylindrical outer shape made in two parts 2, 3 which areassembled in a longitudinal joint plane 4. This stator defines an innervolume defined by a spherical surface 5 having the center'0. This innervolume is defined laterally, on one side by a side wall 6, and, on theother, by a side wall 7 and a planet gear carrier 8.

In the inner volume of the stator I there is disposed a rotor 9 made intwo parts 10, ll assembled in a transverse joint plane 12. Thesemi-rotor 10 has a bearing portion 13journalled in a bearing 14 of theside wall 6 and the semi-rotor 11 has a bearing portion 15 journalled ina bearing 16 of the side wall 7.

The two semi-rotors surround four cylinder liners l7, l8, 19, 20 whichare in opposed relation in pairs on two axes Y-Y, ZZ intersecting at thecentre 0. Each liner is positioned by a rib 21 engaged in a groove 22 ofthe rotor 9. A crankshaft 23 is journalled in a bearing 24 of the rotorand in a bearing 25 of the planet gear carrier 25. The bearings 14, 16,24 and 25 have a common axis X-X passing. through the centre 0 of thespherical inner surface 5 of the stator l. i

A gear pinion 26 connected to rotate with the crankshaft 23 meshes withplanet gears such as 27. Each of these gears 27 is freely rotatable on apin 28 carried by the planet gear carrier and meshes with a'ring gear 29secured to the rotor 9. The number of teeth of the ring gear 29 is equalto four times the number of teeth ofthe gear pinion 26 so that the speedof rotation of the crankshaft is four times that of the rotor inabsolute value, but in the opposite direction.

The crankshaft 23 has a crankpin 30 which is offset or eccentric adistance e from the axisX-X. Mounted on the crankpin 30 to be freelyrotatable is a balancing element 31 having a cylindrical centre bearingportion 32 and two cylindrical lateral bearing portions 33. The bearingportion 32 is offset to one side of the axis of the crankpin 30 to anextent e and bearing portions 33 are offsetto the opposite side of theaxis of the crankpin to the same extent e.

The bearing portion 32 is journalled in a bore formed in a strut 34rigidly interconnecting two opposed pistons 35, 36 which arerespectively slidably mounted in the cylinders 17 and 19. The centre ofthe bearing portion 32 is, on the axis YY, at equal distances from thetwo pistons 35 and 36.

The bearing portions 33 are journalled in bores formed in twohalves of astrut 37 rigidly interconnecting two opposite pistons 38, 39respectively slidably mounted in the cylinders 18 and 20. The centre ofthe bearing portion 33 'is, on the axis ZZ, at equal distances from thetwo pistons 38 and 39.

The volumes defined in each cylinder between the pistons and thespherical surface of the stator constitute the"combustion chambers ofthe engine. A seal between the pistons and the cylinders is afforded bypiston rings 40 and a seal between the rotor and the stator is affordedaround each cylinder by circular rings 41 disposed in grooves of eachliner such as 17. i

The stator half 2'has externally two semicircularpassages 42 receivingthe carburated gases by way of an orifice 43 and communicating with theinterior of the stator by way of induction ports 44, 45.

Exhaust ports 46, 47 are also formed in the stator l which also servesas a support for the spark plugs 48, 49.

The angular distance between the two plugs, or between the inductionports, or between the exhaust ports, is equal to 2/5 of a circumference,namely 144. These various ports and the plugs are moreover suitablydisposed along the periphery of the stator with respect to the upperdead centre and lower dead centre positions of the pistons respectivelydesignated by the letters H 8,, H B H B the rotor rotating in thedirection of arrow F,.

The stator half 3 has an inlet port 50 and a delivery port 51 which areplaced circumferentially between the exhaust port 47 and the inductionport 45. The port 50 is placed between the positions H and B and theport 51 between the positions B and H The engine just described operatesin the following manner:

For'each revolution of the crankshaft with respect to the rotor which isassumed to be fixed, each piston undergoes one to-and-fro movement ineach cylinder.

As the rotor is itself driven in rotation at a quarter of the speed ofthe crankshaft and in the opposite direc tion, for each revolution ofthe rotor each piston undergoes five to-and-fro movements in itscylinder;

As can be seen in FIG. 3, four to-and-fro movements correspond to twocomplete cycles of a four-stroke combustion engine (H H and H H and thefifth 4 to-and-fro movement is employed as an air pump (H and I Thedriving cycles are the following:

ll,, B induction; B H compression; H ignition; H

B expansion; B H exhaust etc.

The pump operation corresponds to: H B suction; B H delivery.

Depending on whether the inlet port 50 or delivery port 51 is connectedto the atmosphere, the pumping operation can be employed as a source ofpulsating air or as a source of suction in very diverse applications:

Thus in an automobile vehicle, the pulsating air can be mixed with theexhaust gases to ensure their postcombustion. This arrangement hasmoreover the advantage of furnishing a supply of air proportionate tothe speed of rotation of the engine.

If the pump is employed as a source of suction, the

vacuum produced can be employed for various control.

devices, for example for braking. This application: is particularlyindicated when the engine according to the invention operates inaccordance with the Diesel cycle, since in this case there isinsufficient suction in the suction manifold for the controls.

It must be understood that the invention is not lim: ited to theembodiment described. Thus in accordance withthe general definition ofthe invention, different ratios may be provided between the speeds ofrotation I of the rotor and crankshaft.

Note, moreover, that an exact balancing of the assembly can be achievedvery simply, since the resultant of the forces of inertia due to thereciprocating masses passes through the crank arm and has a constantmodulus for a given speed. This balancing can then be.

1. In a four-stroke internal combustion engine comi prising a statorhaving induction and exhaust ports, a

rotor mounted to rotate in the stator and defining with the statorcylinders, a crankshaft mounted to rotate in the stator, pistonsslidably mounted in the cylinders and connected to the. crankshaft, anda transmission device interposed between the crankshaft and the rotor toproduce between the crankshaft and the rotor a given relative speed ofrotation; the provision in the stator of additional ports comprising aninlet port and a delivery port, with which additional ports each pistonand corresponding cylinder are cooperable in the course of a part ofeach revolution of the rotor for performing a pumping function.

2. An engine as claimed in claim 1, wherein the crankshaft, has aneccentric crankpin, and a balancing element is rotatably mounted on thecrankpin and definesjournals which are parallel to the axis of the crankand contained in the same plane as the axis of the crankpin, there beingfour cylinders arranged in the form of a cross and having their axesperpendicular to the axis of the crankshaft, and two pairs of pistons,each pair of pistons being mounted to rotate on a journal of thebalancing element, the offset of the crankpin from the axis of thecrankshaft being equal to one half of the distance between saidjournals.

3. An engine as claimed in claim 1, wherein the rotor rotates in thestator about an axis perpendicular to the axes of the cylinders, thetransmission device between the rotor and the crankshaft being such thatthe ratio between the speeds of rotation of the crankshaft and rotor aneven whole number different from +2.

4. An engine as claimed in claim 3, wherein said whole number isnegative.

5. An engine as claimed in claim 3, wherein said whole number ispositive.

6. An engine as claimed in claim 1, wherein the direction of rotation ofthe crankshaft is opposed to that of the rotor and its speed of rotationis four times higher so that it is possible to employ, per revolution ofthe rotor, four to-and-fro movements of each piston to achieve twocomplete four-stroke drive cycles and one to-and-fro movement of thepiston to perform the pumping function through said additional ports.

7. An engine as claimed in claim 1, wherein the whole of the movingparts of the engine are balanced by means of counterweights the centreof gravity of which counterweights is diametrally opposed to the axis ofthe erankpin with respect to the crankshaft axis, the counterweightsbeing carried by the crankshaft.

8. An engine as claimed in claim 7, wherein the crankshaft carries thecounterweights through the medium of an element secured to thecrankshaft to rotate with the crankshaft.

1. In a four-stroke internal combustion engine comprising a statorhaving induction and exhaust ports, a rotor mounted to rotate in thestator and defining with the stator cylinders, a crankshaft mounted torotate in the stator, pistons slidably mounted in the cylinders andconnected to the crankshaft, and a transmission device interposedbetween the crankshaft and the rotor to produce between the crankshaftand the rotor a given relative speed of rotation; the provision in thestator of additional ports comprising an inlet port and a delivery port,with which additional ports each piston and corresponding cylinder arecooperable in the course of a part of each revolution of the rotor forperforming a pumping function.
 2. An engine as claimed in claim 1,wherein the crankshaft has an eccentric crankpin, and a balancingelement is rotatably mounted on the crankpin and defines journals whichare parallel to the axis of the crank and contained in the same plane asthe axis of the crankpin, there being four cylinders arranged in theform of a cross and having their axes perpendicular to the axis of thecrankshaft, and two pairs of pistons, each pair of pistons being mountedto rotate on a journal of the balancing element, the offset of thecrankpin from the axis of the crankshaft being equal to one half of thedistance between said journals.
 3. An engine as claimed in claim 1,wherein the rotor rotates in the stator about an axis perpendicular tothe axes of the cylinders, the transmission device between the rotor andthe crankshaft being such that the ratio between the speeds of rotationof the crankshaft and rotor an even whole number different from +2. 4.An engine as claimed in claim 3, wherein said whole number is negative.5. An engine as claimed in claim 3, wherein said whole number ispositive.
 6. An engine as claimed in claim 1, wherein the direction ofrotation of the crankshaft is opposed to that of the rotor and its speedof rotation is four times higher so that it is possible to employ, perrevolution of the rotor, four to-and-fro movements of each piston toachieve two complete four-stroke drive cycles and one to-and-fromovement of the pIston to perform the pumping function through saidadditional ports.
 7. An engine as claimed in claim 1, wherein the wholeof the moving parts of the engine are balanced by means ofcounterweights the centre of gravity of which counterweights isdiametrally opposed to the axis of the crankpin with respect to thecrankshaft axis, the counterweights being carried by the crankshaft. 8.An engine as claimed in claim 7, wherein the crankshaft carries thecounterweights through the medium of an element secured to thecrankshaft to rotate with the crankshaft.